Hydrogen purification devices, components and fuel processing systems containing the same

ABSTRACT

A hydrogen purification device, components thereof, and fuel processors and fuel cell system containing the same. The hydrogen purification devices include an enclosure that contains a separation assembly adapted to receive a mixed gas stream containing hydrogen gas and to produce a stream that contains pure or at least substantially pure hydrogen gas therefrom. The separation assembly includes at least one hydrogen-permeable and/or hydrogen-selective membrane, and in some embodiments includes at least one membrane envelope that includes a pair of generally opposed membrane regions that define a harvesting conduit therebetween and which are separated by a support. The enclosure includes components that are formed from materials having similar or the same coefficients of thermal expansion as the membrane or membranes. In some embodiments, these components include at least a portion of the support, and in some embodiments, these components include at least a portion of the enclosure.

RELATED APPLICATION

[0001] The present application is a continuation-in-part of and claimspriority to copending U.S. patent application Ser. No. 09/967,172, whichwas filed on Sep. 27, 2001, is entitled “Hydrogen Purification Devices,Components and Fuel Processing Systems Containing the Same,” and thecomplete disclosure of which is hereby incorporated by reference for allpurposes.

FIELD OF THE INVENTION

[0002] The present invention is related generally to the purification ofhydrogen gas, and more specifically to hydrogen purification devices,components and fuel processing and fuel cell systems containing thesame.

BACKGROUND OF THE INVENTION

[0003] Purified hydrogen is used in the manufacture of many productsincluding metals, edible fats and oils, and semiconductors andmicroelectronics. Purified hydrogen is also an important fuel source formany energy conversion devices. For example, fuel cells use purifiedhydrogen and an oxidant to produce an electrical potential. Variousprocesses and devices may be used to produce the hydrogen gas that isconsumed by the fuel cells. However, many hydrogen-production processesproduce an impure hydrogen stream, which may also be referred to as amixed gas stream that contains hydrogen gas. Prior to delivering thisstream to a fuel cell or stack of fuel cells, the mixed gas stream maybe purified, such as to remove undesirable impurities.

SUMMARY OF THE INVENTION

[0004] The present invention is directed to hydrogen purificationdevices, components of hydrogen purification devices, and fuelprocessing and fuel cell systems that include hydrogen purificationdevices. The hydrogen purification devices include an enclosure thatcontains a separation assembly adapted to receive a mixed gas streamcontaining hydrogen gas and to produce a stream that contains pure or atleast substantially pure hydrogen gas therefrom. The separation assemblyincludes at least one hydrogen-permeable and/or hydrogen-selectivemembrane, and in some embodiments includes at least one membraneenvelope that includes a pair of generally opposed membrane regions thatdefine a harvesting conduit therebetween and which are separated by asupport. The enclosure includes components that are formed frommaterials having similar or the same coefficients of thermal expansionas the membrane or membranes. In some embodiments, these componentsinclude at least a portion of the support, and in some embodiments,these components include at least a portion of the enclosure.

[0005] Many other features of the present invention will become manifestto those versed in the art upon making reference to the detaileddescription which follows and the accompanying sheets of drawings inwhich preferred embodiments incorporating the principles of thisinvention are disclosed as illustrative examples only.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]FIG. 1 is a schematic view of a hydrogen purification device.

[0007]FIG. 2 is a schematic cross-sectional view of a hydrogenpurification device having a planar separation membrane.

[0008]FIG. 3 is a schematic cross-sectional view of a hydrogenpurification device having a tubular separation membrane.

[0009]FIG. 4 is a schematic cross-sectional view of another hydrogenpurification device having a tubular separation membrane.

[0010]FIG. 5 is a schematic cross-sectional view of another enclosurefor a hydrogen purification device constructed according to the presentinvention.

[0011]FIG. 6 is a schematic cross-sectional view of another enclosurefor a hydrogen purification device constructed according to the presentinvention.

[0012]FIG. 7 is a fragmentary cross-sectional detail showing anothersuitable interface between components of an enclosure for a purificationdevice according to the present invention.

[0013]FIG. 8 is a fragmentary cross-sectional detail showing anothersuitable interface between components of an enclosure for a purificationdevice according to the present invention.

[0014]FIG. 9 is a fragmentary cross-sectional detail showing anothersuitable interface between components of an enclosure for a purificationdevice according to the present invention.

[0015]FIG. 10 is a fragmentary cross-sectional detail showing anothersuitable interface between components of an enclosure for a purificationdevice according to the present invention.

[0016]FIG. 11 is a top plan view of an end plate for a hydrogenpurification device constructed according to the present invention,including those shown in FIGS. 1-6.

[0017]FIG. 12 is a cross-sectional view of the end plate of FIG. 11.

[0018]FIG. 13 is a top plan view of an end plate for a hydrogenpurification device constructed according to the present invention,including those shown in FIGS. 1-6.

[0019]FIG. 14 is a cross-sectional view of the end plate of FIG. 13.

[0020]FIG. 15 is a top plan view of an end plate for a hydrogenpurification device constructed according to the present invention,including those shown in FIGS. 1-6.

[0021]FIG. 16 is a cross-sectional view of the end plate of FIG. 15.

[0022]FIG. 17 is a top plan view of an end plate for a hydrogenpurification device constructed according to the present invention,including those shown in FIGS. 1-6.

[0023]FIG. 18 is a cross-sectional view of the end plate of FIG. 17.

[0024]FIG. 19 is a top plan view of an end plate for an enclosure for ahydrogen purification device constructed according to the presentinvention, including those shown in FIGS. 1-6.

[0025]FIG. 20 is a cross-sectional view of the end plate of FIG. 19.

[0026]FIG. 21 is a top plan view of an end plate for an enclosure for ahydrogen purification device constructed according to the presentinvention, including those shown in FIGS. 1-6.

[0027]FIG. 22 is a side elevation view of the end plate of FIG. 21.

[0028]FIG. 23 is an isometric view of the end plate of FIG. 21.

[0029]FIG. 24 is a cross-sectional view of the end plate of FIG. 21.

[0030]FIG. 25 is a partial cross-sectional side elevation view of anenclosure for a hydrogen purification device constructed with a pair ofthe end plates shown in FIGS. 21-24.

[0031]FIG. 26 is an isometric view of another hydrogen purificationdevice constructed according to the present invention.

[0032]FIG. 27 is a cross-sectional view of the device of FIG. 26.

[0033]FIG. 28 is a side elevation view of another end plate for ahydrogen purification device constructed according to the presentinvention, including those shown in FIGS. 1-6.

[0034]FIG. 29 is a side elevation view of another end plate for ahydrogen purification device constructed according to the presentinvention, including those shown in FIGS. 1-6.

[0035]FIG. 30 is a side elevation view of another end plate for ahydrogen purification device constructed according to the presentinvention, including those shown in FIGS. 1-6.

[0036]FIG. 31 is a fragmentary side elevation view of a pair ofseparation membranes separated by a support.

[0037]FIG. 32 is an exploded isometric view of a membrane envelopeconstructed according to the present invention and including a supportin the form of a screen structure having several layers.

[0038]FIG. 33 is an exploded isometric view of another membrane envelopeaccording to the present invention.

[0039]FIG. 34 is an exploded isometric view of another membrane envelopeconstructed according to the present invention.

[0040]FIG. 35 is an exploded isometric view of another membrane envelopeconstructed according to the present invention.

[0041]FIG. 36 is a cross-sectional view of a shell for an enclosure fora hydrogen purification device constructed according to the presentinvention with an illustrative membrane frame and membrane module shownin dashed lines.

[0042]FIG. 37 is a top plan view of the end plate of FIG. 13 with anillustrative separation membrane and frame shown in dashed lines.

[0043]FIG. 38 is a top plan view of the end plate of FIG. 21 with anillustrative separation membrane and frame shown in dashed lines.

[0044]FIG. 39 is an exploded isometric view of another hydrogenpurification device constructed according to the present invention.

[0045]FIG. 40 is a schematic diagram of a fuel processing system thatincludes a fuel processor and a hydrogen purification device constructedaccording to the present invention.

[0046]FIG. 41 is a schematic diagram of a fuel processing system thatincludes a fuel processor integrated with a hydrogen purification deviceaccording to the present invention.

[0047]FIG. 42 is a schematic diagram of another fuel processor thatincludes an integrated hydrogen purification device constructedaccording to the present invention.

[0048]FIG. 43 is a schematic diagram of a fuel cell system that includesa hydrogen purification device constructed according to the presentinvention.

DETAILED DESCRIPTION AND BEST MODE OF THE INVENTION

[0049] A hydrogen purification device is schematically illustrated inFIG. 1 and generally indicated at 10. Device 10 includes a body, orenclosure, 12 that defines an internal compartment 18 in which aseparation assembly 20 is positioned. A mixed gas stream 24 containinghydrogen gas 26 and other gases 28 is delivered to the internalcompartment. More specifically, the mixed gas stream is delivered to amixed gas region 30 of the internal compartment and into contact withseparation assembly 20. Separation assembly 20 includes any suitablestructure adapted to receive the mixed gas stream and to producetherefrom a permeate, or hydrogen-rich, stream. Stream 34 typically willcontain pure or at least substantially pure hydrogen gas. However, itwithin the scope of the invention that stream 34 may at least initiallyalso include a carrier, or sweep, gas component.

[0050] In the illustrated embodiment, the portion of the mixed gasstream that passes through the separation assembly enters a permeateregion 32 of the internal compartment. This portion of the mixed gasstream forms hydrogen-rich stream 34, and the portion of the mixed gasstream that does not pass through the separation assembly forms abyproduct stream 36, which contains at least a substantial portion ofthe other gases. In some embodiments, byproduct stream 36 may contain aportion of the hydrogen gas present in the mixed gas stream. It is alsowithin the scope of the invention that the separation assembly isadapted to trap or otherwise retain at least a substantial portion ofthe other gases, which will be removed as a byproduct stream as theassembly is replaced, regenerated or otherwise recharged. In FIG. 1,streams 24-28 are meant to schematically represent that each of streams24-28 may include more that one actual stream flowing into or out ofdevice 10. For example, device 10 may receive plural feed streams 24, asingle stream 24 that is divided into plural streams prior to contactingseparation assembly 20, or simply a single stream that is delivered intocompartment 18.

[0051] Device 10 is typically operated at elevated temperatures and/orpressures. For example, device 10 may be operated at (selected)temperatures in the range of ambient temperatures up to 700° C. or more.In many embodiments, the selected temperature will be in the range of200° C. and 500° C., in other embodiments, the selected temperature willbe in the range of 250° C. and 400° C. and in still other embodiments,the selected temperature will be 400° C.±either 25° C., 50° C. or 75° C.Device 10 may be operated at (selected) pressures in the range ofapproximately 50 psi and 1000 psi or more. In many embodiments, theselected pressure will be in the range of 50 psi and 250 or 500 psi, inother embodiments, the selected pressure will be less than 300 psi orless than 250 psi, and in still other embodiments, the selected pressurewill be 175 psi±either 25 psi, 50 psi or 75 psi. As a result, theenclosure must be sufficiently well sealed to achieve and withstand theoperating pressure.

[0052] It should be understood that as used herein with reference tooperating parameters like temperature or pressure, the term “selected”refers to defined or predetermined threshold values or ranges of values,with device 10 and any associated components being configured to operateat or within these selected values. For further illustration, a selectedoperating temperature may be an operating temperature above or below aspecific temperature, within a specific range of temperatures, or withina defined tolerance from a specific temperature, such as within 5%, 10%,etc. of a specific temperature.

[0053] In embodiments of the hydrogen purification device in which thedevice is operated at an elevated operating temperature, heat needs tobe applied to the device to raise the temperature of the device to theselected operating temperature. For example, this heat may be providedby any suitable heating assembly 42. Illustrative examples of heatingassembly 42 have been schematically illustrated in FIG. 1. It should beunderstood that assembly 42 may take any suitable form, including mixedgas stream 24 itself. Illustrative examples of other suitable heatingassemblies include one or more of a resistance heater, a burner or othercombustion region that produces a heated exhaust stream, heat exchangewith a heated fluid stream other than mixed gas stream 24, etc. When aburner or other combustion chamber is used, a fuel stream is consumedand byproduct stream 36 may form all or a portion of this fuel stream.At 42′ in FIG. 1, schematic representations have been made to illustratethat the heating assembly may deliver the heated fluid stream externaldevice 10, such as within a jacket that surrounds or at least partiallysurrounds the enclosure, by a stream that extends into the enclosure orthrough passages in the enclosure, or by conduction, such as with anelectric resistance heater or other device that radiates or conductselectrically generated heat.

[0054] A suitable structure for separation assembly 20 is one or morehydrogen-permeable and/or hydrogen-selective membranes 46. The membranesmay be formed of any hydrogen-permeable material suitable for use in theoperating environment and parameters in which purification device 10 isoperated. Examples of suitable materials for membranes 46 includepalladium and palladium alloys, and especially thin films of such metalsand metal alloys. Palladium alloys have proven particularly effective,especially palladium with 35 wt % to 45 wt % copper, such as a membranethat contains 40 wt % copper. These membranes are typically formed froma thin foil that is approximately 0.001 inches thick. It is within thescope of the present invention, however, that the membranes may beformed from hydrogen-permeable and/or hydrogen-selective materials,including metals and metal alloys other than those discussed above aswell as non-metallic materials and compositions, and that the membranesmay have thicknesses that are greater or less than discussed above. Forexample, the membrane may be made thinner, with commensurate increase inhydrogen flux. Examples of suitable mechanisms for reducing thethickness of the membranes include rolling, sputtering and etching. Asuitable etching process is disclosed in U.S. Pat. No. 6,152,995, thecomplete disclosure of which is hereby incorporated by reference for allpurposes. Examples of various membranes, membrane configurations, andmethods for preparing the same are disclosed in U.S. Pat. No. 6,221,117and U.S. patent application Ser. No. 09/812,499, the completedisclosures of which are hereby incorporated by reference for allpurposes.

[0055] In FIG. 2, illustrative examples of suitable configurations formembranes 46 are shown. As shown, membrane 46 includes a mixed-gassurface 48 which is oriented for contact by mixed gas stream 24, and apermeate surface 50, which is generally opposed to surface 48. Alsoshown at 52 are schematic representations of mounts, which may be anysuitable structure for supporting and/or positioning the membranes orother separation assemblies within compartment 18. The patent and patentapplications incorporated immediately above also disclose illustrativeexamples of suitable mounts 52. At 46′, membrane 46 is illustrated as afoil or film. At 46″, the membrane is supported by an underlying support54, such as a mesh or expanded metal screen or a ceramic or other porousmaterial. At 46″′, the membrane is coated or formed onto or otherwisebonded to a porous member 56. It should be understood that the membraneconfigurations discussed above have been illustrated schematically inFIG. 2 and are not intended to represent every possible configurationwithin the scope of the invention.

[0056] For example, although membrane 46 is illustrated in FIG. 2 ashaving a planar configuration, it is within the scope of the inventionthat membrane 46 may have non-planar configurations as well. Forexample, the shape of the membrane may be defined at least in part bythe shape of a support 54 or member 56 upon which the membrane issupported and/or formed. As such, membranes 46 may have concave, convexor other non-planar configurations, especially when device 10 isoperating at an elevated pressure. As another example, membrane 46 mayhave a tubular configuration, such as shown in FIGS. 3 and 4.

[0057] In FIG. 3, an example of a tubular membrane is shown in which themixed gas stream is delivered to the interior of the membrane tube. Inthis configuration, the interior of the membrane tube defines region 30of the internal compartment, and the permeate region 32 of thecompartment lies external the tube. An additional membrane tube is shownin dashed lines in FIG. 3 to represent graphically that it is within thescope of the present invention that device 10 may include more than onemembrane and/or more than one mixed-gas surface 48. It is within thescope of the invention that device 10 may also include more than twomembranes, and that the relative spacing and/or configuration of themembranes may vary.

[0058] In FIG. 4, another example of a hydrogen purification device 10that includes tubular membranes is shown. In this illustratedconfiguration, device 10 is configured so that the mixed gas stream isdelivered into compartment 18 external to the membrane tube or tubes. Insuch a configuration, the mixed-gas surface of a membrane tube isexterior to the corresponding permeate surface, and the permeate regionis located internal the membrane tube or tubes.

[0059] The tubular membranes may have a variety of configurations andconstructions, such as those discussed above with respect to the planarmembranes shown in FIG. 2. For example, illustrative examples of variousmounts 52, supports 54 and porous members 56 are shown in FIGS. 3 and 4,including a spring 58, which has been schematically illustrated. It isfurther within the scope of the invention that tubular membranes mayhave a configuration other than the straight cylindrical tube shown inFIG. 3. Examples of other configurations include U-shaped tubes andspiral or helical tubes.

[0060] As discussed, enclosure 12 defines a pressurized compartment 18in which separation assembly 20 is positioned. In the embodiments shownin FIGS. 2-4, enclosure 12 includes a pair of end plates 60 that arejoined by a perimeter shell 62. It should be understood that device 10has been schematically illustrated in FIGS. 2-4 to show representativeexamples of the general components of the device without intending to belimited to geometry, shape and size. For example, end plates 60typically are thicker than the walls of perimeter shell 62, but this isnot required. Similarly, the thickness of the end plates may be greaterthan, less than or the same as the distance between the end plates. As afurther example, the thickness of membrane 46 has been exaggerated forpurposes of illustration.

[0061] In FIGS. 2-4, it can be seen that mixed gas stream 24 isdelivered to compartment 18 through an input port 64, hydrogen-rich (orpermeate) stream 34 is removed from device 10 through one or moreproduct ports 66, and the byproduct stream is removed from device 10through one or more byproduct ports 68. In FIG. 2, the ports are shownextending through various ones of the end plates to illustrate that theparticular location on enclosure 12 from which the gas streams aredelivered to and removed from device 10 may vary. It is also within thescope of the invention that one or more of the streams may be deliveredor withdrawn through shell 62, such as illustrated in dashed lines inFIG. 3. It is further within the scope of the invention that ports 64-68may include or be associated with flow-regulating and/or couplingstructures. Examples of these structures include one or more of valves,flow and pressure regulators, connectors or other fittings and/ormanifold assemblies that are configured to permanently or selectivelyfluidly interconnect device 10 with upstream and downstream components.For purposes of illustration, these flow-regulating and/or couplingstructures are generally indicated at 70 in FIG. 2. For purposes ofbrevity, structures 70 have not been illustrated in every embodiment.Instead, it should be understood that some or all of the ports for aparticular embodiment of device 10 may include any or all of thesestructures, that each port does not need to have the same, if any,structure 70, and that two or more ports may in some embodiments shareor collectively utilize structure 70, such as a common collection ordelivery manifold, pressure relief valve, fluid-flow valve, etc.

[0062] End plates 60 and perimeter shell 62 are secured together by aretention structure 72. Structure 72 may take any suitable form capableof maintaining the components of enclosure 12 together in a fluid-tightor substantially fluid-tight configuration in the operating parametersand conditions in which device 10 is used. Examples of suitablestructures 72 include welds 74 and bolts 76, such as shown in FIGS. 2and 3. In FIG. 3, bolts 76 are shown extending through flanges 78 thatextend from the components of enclosure 12 to be joined. In FIG. 4,bolts 76 are shown extending through compartment 18. It should beunderstood that the number of bolts may vary, and typically will includea plurality of bolts or similar fastening mechanisms extending aroundthe perimeter of enclosure 18. Bolts 76 should be selected to be able towithstand the operating parameters and conditions of device 10,including the tension imparted to the bolts when device 10 ispressurized.

[0063] In the lower halves of FIGS. 3 and 4, gaskets 80 are shown toillustrate that enclosure 12 may, but does not necessarily, include aseal member 82 interconnecting or spanning the surfaces to be joined toenhance the leak-resistance of the enclosure. The seal member should beselected to reduce or eliminate leaks when used at the operatingparameters and under the operating conditions of the device. Therefore,in many embodiments, high-pressure and/or high-temperature seals shouldbe selected. An illustrative, non-exclusive example of such a sealstructure is a graphite gasket, such as sold by Union Carbide under thetrade name GRAFOIL™. As used herein, “seal member” and “sealing member”are meant to refer to structures or materials applied to, placedbetween, or placed in contact with the metallic end plates and shell (orshell portions) to enhance the seal established therebetween. Gaskets orother sealing members may also be used internal compartment 18, such asto provide seals between adjacent membranes, fluid conduits, mounts orsupports, and/or any of the above with the internal surface of enclosure12.

[0064] In FIGS. 2-4, the illustrated enclosures include a pair of endplates 60 and a shell 62. With reference to FIG. 4, it can be seen thatthe end plates include sealing regions 90, which form an interface 94with a corresponding sealing region 92 of shell 62. In many embodiments,the sealing region of end plate 60 will be perimeter region, and assuch, sealing region 90 will often be referred to herein as a perimeterregion 90 of the end plate. However, as used herein, the perimeterregion is meant to refer to the region of the end plate that extendsgenerally around the central region and which forms an interface with aportion of the shell, even if there are additional portions or edges ofthe end plate that project beyond this perimeter portion. Similarly,sealing region 92 of shell 62 will typically be an end region of theshell. Accordingly, the sealing region of the shell will often bereferred to herein as end region 92 of the shell. It is within the scopeof the invention, however, that end plates 60 may have portions thatproject outwardly beyond the sealing region 90 and interface 94 formedwith shell 62, and that shell 62 may have regions that project beyondend plate 60 and the interface formed therewith. These portions areillustrated in dashed lines in FIG. 4 at 91 and 93 for purposes ofgraphical illustration.

[0065] As an alternative to a pair of end plates 60 joined by a separateperimeter shell 62, enclosure 12 may include a shell that is at leastpartially integrated with either or both of the end plates. For example,in FIG. 5, a portion 63 of shell 62 is integrally formed with each endplate 60. Described another way, each end plate 60 includes shellportions, or collars, 63 that extend from the perimeter region 90 of theend plate. As shown, the shell portions include end regions 92 whichintersect at an interface 94. In the illustrated embodiment, the endregions abut each other without a region of overlap; however, it iswithin the scope of the invention that interface 94 may have otherconfigurations, such as those illustrated and/or described subsequently.End regions 92 are secured together via any suitable mechanism, such asby any of the previously discussed retention structures 72, and may (butdo not necessarily) include a seal member 82 in addition to the matingsurfaces of end regions 92.

[0066] A benefit of shell 62 being integrally formed with at least oneof the end plates is that the enclosure has one less interface that mustbe sealed. This benefit may be realized by reduced leaks due to thereduced number of seals that could fail, fewer components, and/or areduced assembly time for device 10. Another example of such aconstruction for enclosure 12 is shown in FIG. 6, in which the shell 62is integrally formed with one of the end plates, with a shell portion 63that extends integrally from the perimeter region 90 of one of the endplates. Shell portion 63 includes an end region 92 that forms aninterface 94 with the perimeter region 90 of the other end plate via anysuitable retention structure 72, such as those described above. Thecombined end plate and shell components shown in FIGS. 5 and 6 may beformed via any suitable mechanism, including machining them from a solidbar or block of material. For purposes of simplicity, separationassembly 20 and the input and output ports have not been illustrated inFIGS. 5 and 6 and only illustrative, non-exclusive examples of suitableretention structure 72 are shown. Similar to the other enclosuresillustrated and described herein, it should be understood that therelative dimensions of the enclosure may vary and still be within thescope of the invention. For example, shell portions 63 may have lengthsthat are longer or shorter than those illustrated in FIGS. 5 and 6.

[0067] Before proceeding to additional illustrative configurations forend plates 60, it should be clarified that as used herein in connectionwith the enclosures of devices 10, the term “interface” is meant torefer to the interconnection and sealing region that extends between theportions of enclosure 12 that are separately formed and thereaftersecured together, such as (but not necessarily) by one of the previouslydiscussed retention structures 72. The specific geometry and size ofinterface 94 will tend to vary, such as depending upon size,configuration and nature of the components being joined together.Therefore, interface 94 may include a metal-on-metal seal formed betweencorresponding end regions and perimeter regions, a metal-on-metal sealformed between corresponding pairs of end regions, a metal-gasket (orother seal member 82)-metal seal, etc. Similarly, the interface may havea variety of shapes, including linear, arcuate and rectilinearconfigurations that are largely defined by the shape and relativeposition of the components being joined together.

[0068] For example, in FIG. 6, an interface 94 extends between endregion 92 of shell portion 63 and perimeter region 90 of end plate 60.As shown, regions 90 and 92 intersect with parallel edges. As discussed,a gasket or other seal member may extend between these edges. In FIGS.7-10, nonexclusive examples of additional interfaces 94 that are withinthe scope of the invention are shown. Embodiments of enclosure 12 thatinclude an interface 94 formed between adjacent shell regions may alsohave any of these configurations. In FIG. 7, perimeter region 90 definesa recess or corner into which end region 92 of shell 62 extends to forman interface 94 that extends around this comer. Also shown in FIG. 7 iscentral region 96 of end plate 60, which as illustrated extends withinshell 62 and defines a region of overlap therewith.

[0069] In FIG. 8, perimeter region 90 defines a corner that opensgenerally toward compartment 18, as opposed to the corner of FIG. 7,which opens generally away from compartment 18. In the configurationshown in FIG. 8, perimeter region 90 includes a collar portion 98 thatextends at least partially along the outer surface 100 of shell 62 todefine a region of overlap therewith. Central region 96 of plate 60 isshown in solid lines extending along end region 92 without extendinginto shell 62, in dashed lines extending into shell 62, and in dash-dotlines including an internal support 102 that extends at least partiallyalong the inner surface 104 of shell 60. FIGS. 9 and 10 are similar toFIGS. 7 and 8 except that perimeter region 90 and end region 92 areadapted to threadingly engage each other, and accordingly includecorresponding threads 106 and 108. In dashed lines in FIG. 9, anadditional example of a suitable configuration for perimeter region 90of end plate 60 is shown. As shown, the outer edge 110 of the end platedoes not extend radially (or outwardly) to or beyond the exteriorsurface of shell 62.

[0070] It should be understood that any of these interfaces may be usedwith an enclosure constructed according to the present invention.However, for purposes of brevity, every embodiment of enclosure 12 willnot be shown with each of these interfaces. Therefore, although thesubsequently described end plates shown in FIGS. 11-31 are shown withthe interface configuration of FIG. 7, it is within the scope of theinvention that the end plates and corresponding shells may be configuredto have any of the interfaces described and/or illustrated herein, aswell as the integrated shell configuration described and illustratedwith respect to FIGS. 5 and 6. Similarly, it should be understood thatthe devices constructed according to the present invention may have anyof the enclosure configurations, interface configurations, retentionstructure configurations, separation assembly configurations,flow-regulating and/or coupling structures, seal member configurations,and port configurations discussed, described and/or incorporated herein.Similarly, although the following end plate configurations areillustrated with circular perimeters, it is within the scope of theinvention that the end plates may be configured to have perimeters withany other geometric configuration, including arcuate, rectilinear, andangular configurations, as well as combinations thereof.

[0071] As discussed, the dimensions of device 10 and enclosure 12 mayalso vary. For example, an enclosure designed to house tubularseparation membranes may need to be longer (i.e. have a greater distancebetween end plates) than an enclosure designed to house planarseparation membranes to provide a comparable amount of membrane surfacearea exposed to the mixed gas stream (i.e., the same amount of effectivemembrane surface area). Similarly, an enclosure configured to houseplanar separation membranes may tend to be wider (i.e., have a greatercross-sectional area measured generally parallel to the end plates) thanan enclosure designed to house tubular separation membranes. However, itshould be understood that neither of these relationships are required,and that the specific size of the device and/or enclosure may vary.Factors that may affect the specific size of the enclosure include thetype and size of separation assembly to be housed, the operatingparameters in which the device will be used, the flow rate of mixed gasstream 24, the shape and configuration of devices such as heatingassemblies, fuel processors and the like with which or within which thedevice will be used, and to some degree, user preferences.

[0072] As discussed previously, hydrogen purification devices may beoperated at elevated temperatures and/or pressures. Both of theseoperating parameters may impact the design of enclosures 12 and othercomponents of the devices. For example, consider a hydrogen purificationdevice 10 operated at a selected operating temperature above an ambienttemperature, such as a device operating at 400° C. As an initial matter,the device, including enclosure 12 and separation assembly 20, must beconstructed from a material that can withstand the selected operatingtemperature, and especially over prolonged periods of time and/or withrepeated heating and cooling off cycles. Similarly, the materials thatare exposed to the gas streams preferably are not reactive or at leastnot detrimentally reactive with the gases. An example of a suitablematerial is stainless steel, such as Type 304 stainless steel, althoughothers may be used.

[0073] Besides the thermal and reactive stability described above,operating device 10 at a selected elevated temperature requires one ormore heating assemblies 42 to heat the device to the selected operatingtemperature. When the device is initially operated from a shutdown, orunheated, state, there will be an initial startup or preheating periodin which the device is heated to the selected operating temperature.During this period, the device may not produce a hydrogen-rich stream atall, a hydrogen-rich stream that contains more than an acceptable levelof the other gases, and/or a reduced flow rate of the hydrogen-richstream compared to the byproduct stream or streams (meaning that agreater percentage of the hydrogen gas is being exhausted as byproductinstead of product). In addition to the time to heat the device, onemust also consider the heat or thermal energy required to heat thedevice to the selected temperature. The heating assembly or assembliesmay add to the operating cost, materials cost, and/or equipment cost ofthe device. For example, a simplified end plate 60 is a relatively thickslab having a uniform thickness. In fact, stainless steel plates havinga uniform thickness of 0.5″ or 0.75 inches have proven effective tosupport and withstand the operating parameters and conditions of device10. However, the dimensions of these plates add considerable weight todevice 10, and in many embodiments require considerable thermal energyto be heated to the selected operating temperature. As used herein, theterm “uniform thickness” is meant to refer to devices that have aconstant or at least substantially constant thickness, including thosethat deviate in thickness by a few (less than 5%) along their lengths.In contrast, and as used herein, a “variable thickness” will refer to athickness that varies by at least 10%, and in some embodiments at least25%, 40% or 50%.

[0074] The pressure at which device 10 is operated may also affect thedesign of device 10, including enclosure 12 and separation assembly 20.Consider for example a device operating at a selected pressure of 175psi. Device 10 must be constructed to be able to withstand the stressesencountered when operating at the selected pressure. This strengthrequirement affects not only the seals formed between the components ofenclosure 12, but also the stresses imparted to the componentsthemselves. For example, deflection or other deformation of the endplates and/or shell may cause gases within compartment 18 to leak fromthe enclosure. Similarly, deflection and/or deformation of thecomponents of the device may also cause unintentional mixing of two ormore of gas streams 24, 34 and 36. For example, an end plate may deformplastically or elastically when subjected to the operating parametersunder which device 10 is used. Plastic deformation results in apermanent deformation of the end plate, the disadvantage of whichappears fairly evident. Elastic deformation, however, also may impairthe operation of the device because the deformation may result ininternal and/or external leaks. More specifically, the deformation ofthe end plates or other components of enclosure 12 may enable gases topass through regions where fluid-tight seals previously existed. Asdiscussed, device 10 may include gaskets or other seal members to reducethe tendency of these seals to leak, however, the gaskets have a finitesize within which they can effectively prevent or limit leaks betweenopposing surfaces. For example, internal leaks may occur in embodimentsthat include one or more membrane envelopes or membrane platescompressed (with or without gaskets) between the end plates. As the endplates deform and deflect away from each other, the plates and/orgaskets may in those regions not be under the same tension orcompression as existed prior to the deformation. Gaskets, or gasketplates, may be located between a membrane envelope and adjacent feedplates, end plates, and/or other adjacent membrane envelopes. Similarly,gaskets or gasket plates may also be positioned within a membraneenvelope to provide additional leak prevention within the envelope.

[0075] In view of the above, it can be seen that there are two or threecompeting factors to be weighed with respect to device 10. In thecontext of enclosure 12, the heating requirements of the enclosure willtend to increase as the materials used to form the enclosure arethickened. To some degree using thicker materials may increase thestrength of the enclosure, however, it may also increase the heating andmaterial requirements, and in some embodiments actually produce regionsto which greater stresses are imparted compared to a thinner enclosure.Areas to monitor on an end plate include the deflection of the endplate, especially at the perimeter regions that form interface(s) 94,and the stresses imparted to the end plate.

[0076] Consider for example a circular end plate formed from Type 304stainless steel and having a uniform thickness of 0.75 inches. Such anend plate weights 7.5 pounds. A hydrogen purification device containingthis end plate was exposed to operating parameters of 400° C. and 175psi. Maximum stresses of 25,900 psi were imparted to the end plate, witha maximum deflection of 0.0042 inches and a deflection at perimeterregion 90 of 0.0025 inches.

[0077] Another end plate 60 constructed according to the presentinvention is shown in FIGS. 11 and 12 and generally indicated at 120. Asshown, end plate 120 has interior and exterior surfaces 122 and 124.Interior surface 122 includes central region 96 and perimeter region 90.Exterior surface 124 has a central region 126 and a perimeter region128, and in the illustrated embodiment, plate 120 has a perimeter 130extending between the perimeter regions 90 and 128 of the interior andexterior surfaces. As discussed above, perimeter region 90 may have anyof the configurations illustrated or described above, including aconfiguration in which the sealing region is at least partially orcompletely located along perimeter 130. In the illustrated embodiment,perimeter 130 has a circular configuration. However, it is within thescope of the invention that the shape may vary, such as to includerectilinear and other arcuate, geometric, linear, and/or corneredconfigurations.

[0078] Unlike the previously illustrated end plates, however, thecentral region of the end plate has a variable thickness between itsinterior and exterior surfaces, which is perhaps best seen in FIG. 12.Unlike a uniform slab of material, the exterior surface of plate 120 hasa central region 126 that includes an exterior cavity, or removedregion, 132 that extends into the plate and generally toward centralregion 96 on interior surface 122. Described another way, the end platehas a nonplanar exterior surface, and more specifically, an exteriorsurface in which at least a portion of the central region extends towardthe corresponding central region of the end plate's interior surface.Region 132 reduces the overall weight of the end plate compared to asimilarly constructed end plate that does not include region 132. Asused herein, removed region 132 is meant to exclude ports or other boresthat extend completely through the end plates. Instead, region 132extends into, but not through, the end plate.

[0079] A reduction in weight means that a purification device 10 thatincludes the end plate will be lighter than a corresponding purificationdevice that includes a similarly constructed end plate formed withoutregion 132. With the reduction in weight also comes a correspondingreduction in the amount of heat (thermal energy) that must be applied tothe end plate to heat the end plate to a selected operating temperature.In the illustrated embodiment, region 132 also increases the surfacearea of exterior surface 124. Increasing the surface area of the endplate compared to a corresponding end plate may, but does notnecessarily in all embodiments, increase the heat transfer surface ofthe end plate, which in turn, can reduce the heating requirements and/ortime of a device containing end plate 120.

[0080] In some embodiments, plate 120 may also be described as having acavity that corresponds to, or includes, the region of maximum stress ona similarly constructed end plate in which the cavity was not present.Accordingly, when exposed to the same operating parameters andconditions, lower stresses will be imparted to end plate 120 than to asolid end plate formed without region 132. For example, in the solid endplate with a uniform thickness, the region of maximum stress occurswithin the portion of the end plate occupied by removed region 132 inend plate 120. Accordingly, an end plate with region 132 mayadditionally or alternatively be described as having a stress abatementstructure 134 in that an area of maximum stress that would otherwise beimparted to the end plate has been removed.

[0081] For purposes of comparison, consider an end plate 120 having theconfiguration shown in FIGS. 11 and 12, formed from Type 304 stainlesssteel, and having a diameter of 6.5 inches. This configurationcorresponds to maximum plate thickness of 0.75 inches and a removedregion 132 having a length and width of 3 inches. When utilized in adevice 10 operating at 400° C. and 175 psi, plate 120 has a maximumstress imparted to it of 36,000 psi, a maximum deflection of 0.0078inches, a displacement of 0.0055 inches at perimeter region 90, and aweight of 5.7 pounds. It should be understood that the dimensions andproperties described above are meant to provide an illustrative exampleof the combinations of weight, stress and displacement experienced byend plates according to the present invention, and that the specificperimeter shape, materials of construction, perimeter size, thickness,removed region shape, removed region depth and removed region perimeterall may vary within the scope of the invention.

[0082] In FIG. 11, it can be seen that region 132 (and/or stressabatement structure 134) has a generally square or rectilinearconfiguration measured transverse to surfaces 122 and 124. As discussed,other geometries and dimensions may be used and are within the scope ofthe invention. To illustrate this point, variations of end plate 120 areshown in FIGS. 13-16 and generally indicated at 120′ and 120″. In thesefigures, region 132 is shown having a circular perimeter, with thedimensions of the region being smaller in FIGS. 13 and 14 than in FIGS.15 and 16.

[0083] For purposes of comparison, consider an end plate 120 having theconfiguration shown in FIGS. 13 and 14 and having the same materials ofconstruction, perimeter and thickness as the end plate shown in FIGS. 11and 12. Instead of the generally square removed region of FIGS. 11 and12, however, end plate 120′ as a removed region with a generallycircular perimeter and a diameter of 3.25 inches. End plate 120′ weighsthe same as end plate 120, but has reduced maximum stress anddeflections. More specifically, while end plate 120 had a maximum stressgreater than 35,000 psi, end plate 120′ had a maximum stress that isless than 30,000 psi, and in the illustrated configuration less than25,000 psi, when subjected to the operating parameters discussed abovewith respect to plate 120. In fact, plate 120′ demonstratedapproximately a 35% reduction in maximum stress compared to plate 120.The maximum and perimeter region deflections of plate 120′ were alsoless than plate 120, with a measured maximum deflection of 0.007 inchesand a measured deflection at perimeter region 90 of 0.0050 inches.

[0084] End plate 120″, which is shown in FIGS. 15 and 16 is similar toend plate 120′, except region 132 (and/or structure 134) has a diameterof 3.75 inches instead of 3.25 inches. This change in the size of theremoved region decreases the weight of the end plate to 5.3 pounds andproduced the same maximum deflection. End plate 120″ also demonstrated amaximum stress that is less than 25,000 psi, although approximately 5%greater than that of end plate 120′ (24,700 psi, compared to 23,500psi). At perimeter region 90, end plate 120″ exhibited a maximumdeflection of 0.0068 inches.

[0085] In FIGS. 13-16, illustrative port configurations have been shown.In FIGS. 13 and 14, a port 138 is shown in dashed lines extending frominterior surface 122 through the end plate to exterior surface 124.Accordingly, with such a configuration a gas stream is delivered orremoved via the exterior surface of the end plate of device 10. In sucha configuration, fluid conduits and/or flow-regulating and/or couplingstructure 70 typically will project from the exterior surface 124 of theend plate. Another suitable configuration is indicated at 140 in dashedlines in FIGS. 15 and 16. As shown, port 140 extends from the interiorsurface of the end plate then through perimeter 130 instead of exteriorsurface 124. Accordingly, port 140 enables gas to be delivered orremoved from the perimeter of the end plate instead of the exteriorsurface of the end plate. It should be understood that ports 64-68 mayhave these configurations illustrated by ports 138 and 140. Of course,ports 64-68 may have any other suitable port configuration as well,including a port that extends through shell 62 or a shell portion. Forpurposes of simplicity, ports will not be illustrated in many of thesubsequently described end plates, just as they were not illustrated inFIGS. 5 and 6.

[0086] Also shown in dashed lines in FIGS. 13-15 are guide structures144. Guide structures 144 extend into compartment 18 and providesupports that may be used to position and/or align separation assembly20, such as membranes 46. In some embodiments, guide structures 144 maythemselves form mounts 52 for the separation assembly. In otherembodiments, the device includes mounts other than guide structures 144.Guide structures may be used with any of the end plates illustrated,incorporated and/or described herein, regardless of whether any suchguide structures are shown in a particular drawing figure. However, itshould also be understood that hydrogen purification devices accordingto the present invention may be formed without guide structures 144. Inembodiments of device 10 that include guide structures 144 that extendinto or through compartment 18, the number of such structures may varyfrom a single support to two or more supports. Similarly, while guidestructures 144 have been illustrated as cylindrical ribs or projections,other shapes and configurations may be used within the scope of theinvention.

[0087] Guide structures 144 may be formed from the same materials as thecorresponding end plates. Additionally or alternatively, the guidestructures may include a coating or layer of a different material. Guidestructures 144 may be either separately formed from the end plates andsubsequently attached thereto, or integrally formed therewith. Guidestructures 144 may be coupled to the end plates by any suitablemechanism, including attaching the guide structures to the interiorsurfaces of the end plates, inserting the guide structures into boresextending partially through the end plates from the interior surfacesthereof, or inserting the guide structures through bores that extendcompletely through the end plates. In embodiments where the end platesinclude bores that extend completely through the end plates (which aregraphically illustrated for purposes of illustration at 146 in FIG. 14),the guide structures may be subsequently affixed to the end plates.Alternatively, the guide structures may be inserted through compartment18 until the separation assembly is properly assigned and securedtherein, and then the guide structures may be removed and the boressealed (such as by welding) to prevent leaks.

[0088] In FIGS. 17 and 18, another end plate 60 constructed according tothe present invention is shown and generally indicated at 150. Unlessotherwise specified, it should be understood that end plates 150 mayhave any of the elements, subelements and variations as any of the otherend plates shown, described and/or incorporated herein. Similar to endplate 120′, plate 150 includes an exterior surface 124 with a removedregion 132 (and/or stress abatement structure 134) having a circularperimeter with a diameter of 3.25 inches. Exterior surface 124 furtherincludes an outer removed region 152 that extends from central region126 to perimeter portion 128. Outer removed region 152 decreases inthickness as it approaches perimeter 130. In the illustrated embodiment,region 152 has a generally linear reduction in thickness, although otherlinear and arcuate transitions may be used. For example, a variation ofend plate 150 is shown in FIGS. 19 and 20 and generally indicated at150′. End plate 150′ also includes central and exterior removed regions132 and 152, with exterior surface 124 having a generally semitoroidalconfiguration as it extends from central region 126 to perimeter region128. To demonstrate that the size of region 132 (which will also bereferred to as a central removed region, such as when embodied on an endplate that also includes an outer removed region), may vary, end plate150′ includes a central removed region having a diameter of 3 inches.

[0089] For purposes of comparison, both end plates 150 and 150′ havereduced weights compared to end plates 120, 120′ and 120″. Plate 150weighed 4.7 pounds, and plate 150′ weighed 5.1 pounds. Both end plates150 and 150′ experienced maximum stresses of 25,000 psi or less whensubjected to the operating parameters discussed above (400° C. and 175psi), with plate 150′ having a 5% lower stress than plate 150 (23,750psi compared to 25,000 psi). The maximum deflection of the plates were0.0098 inches and 0.008 inches, respectively, and the displacement atperimeter regions 90 were 0.0061 inches and 0.0059 inches, respectively.

[0090] Another end plate 60 constructed according to the presentinvention is shown in FIGS. 21-24 and generally indicated at 160. Unlessotherwise specified, end plate 160 may have the same elements,subelements and variations as the other end plates illustrated,described and/or incorporated herein. End plate 160 may be referred toas a truss-stiffened end plate because it includes a truss assembly 162that extends from the end plate's exterior surface 124. As shown, endplate 160 has a base plate 164 with a generally planar configuration,similar to the end plates shown in FIGS. 2-5. However, truss assembly162 enables, but does not require, that the base plate may have athinner construction while still providing comparable if not reducedmaximum stresses and deflections. It is within the scope of theinvention that any of the other end plates illustrated, described and/orincorporated herein also may include a truss assembly 162.

[0091] Truss assembly 162 extends from exterior surface 124 of baseplate 164 and includes a plurality of projecting ribs 166 that extendfrom exterior surface 124. In FIGS. 21-24, it can be seen that ribs 166are radially spaced around surface 124. Nine ribs 166 are shown in FIGS.21 and 23, but it is within the scope of the invention that trussassembly 162 may be formed with more or fewer ribs. Similarly, in theillustrated embodiment, ribs 166 have arcuate configurations, andinclude flanges 168 extending between the ribs and surface 124. Flanges168 may also be described as heat transfer fins because they addconsiderable heat transfer area to the end plate. Truss assembly 162further includes a tension collar 170 that interconnects the ribs. Asshown, collar 170 extends generally parallel to surface base plate 164and has an open central region 172. Collar 170 may be formed with aclosed or internally or externally projecting central portion withoutdeparting from the invention. To illustrate this point, members 174 areshown in dashed lines extending across collar 170 in FIG. 21. Similarly,collar 170 may have configurations other than the circular configurationshown in FIGS. 21-24. As a further alternative, base plate 164 has beenindicated in partial dashed lines in FIG. 22 to graphically illustratethat the base plate may have a variety of configurations, such as thosedescribed, illustrated and incorporated herein, including theconfiguration shown if the dashed region is removed.

[0092] End plate 160 may additionally, or alternatively, be described ashaving a support 170 that extends in a spaced-apart relationship beyondexterior surface 124 of base plate 164 and which is adapted to provideadditional stiffness and/or strength to the base plate. Still anotheradditional or alternative description of end plate 160 is that the endplate includes heat transfer structure 162 extending away from theexterior surface of the base plate, and that the heat transfer structureincludes a surface 170 that is spaced-away from surface 124 such that aheated fluid stream may pass between the surfaces.

[0093] Truss assembly 162 may also be referred to as an example of adeflection abatement structure because it reduces the deflection thatwould otherwise occur if base plate 164 were formed without the trussassembly. Similarly, truss assembly 162 may also provide another exampleof a stress abatement restructure because it reduces the maximumstresses that would otherwise be imparted to the base plate.Furthermore, the open design of the truss assembly increases the heattransfer area of the base plate without adding significant weight to thebase plate.

[0094] Continuing the preceding comparisons between end plates, plate160 was subjected to the same operating parameters as the previouslydescribed end plates. The maximum stresses imparted to base plate 164were 10,000 psi or less. Similarly, the maximum deflection of the baseplate was only 0.0061 inches, with a deflection of 0.0056 inches atperimeter region 90. It should be noted, that base plate 160 achievedthis significant reduction in maximum stress while weighing only 3.3pounds. Similarly, base plate 164 experienced a smaller maximumdisplacement and comparable or reduced perimeter displacement yet had abase plate that was only 0.25 inches thick. Of course, plate 160 may beconstructed with thicker base plates, but the tested plate proved to besufficiently strong and rigid under the operating parameters with whichit was used.

[0095] As discussed, enclosure 12 may include a pair of end plates 60and a perimeter shell. In FIG. 25, an example of an enclosure 12 formedwith a pair of end plates 160 is shown for purposes of illustration andindicated generally at 180. Although enclosure 180 has a pair oftruss-stiffened end plates 160, it is within the scope of the inventionthat an enclosure may have end plates having different constructionsand/or configurations. In fact, in some operating environments it may bebeneficial to form enclosure 12 with two different types of end plates.In others, it may be beneficial for the end plates to have the sameconstruction.

[0096] In FIGS. 26 and 27 another example of an enclosure 12 is shownand generally indicated at 190 and includes end plates 120″′. End plates120″′ have a configuration similar to FIGS. 13-16, except removed region132 is shown having a diameter of 4 inches to further illustrate thatthe shape and size of the removed region may vary within the scope ofthe invention. Both end plates include shell portions 63 extendingintegrally therefrom to illustrate that any of the end platesillustrated, described, and/or incorporated herein may include a shellportion 63 extending integrally therefrom. To illustrate that any of theend plates described, illustrated and/or incorporated herein may alsoinclude truss assemblies (or heat transfer structure) 162 and/orprojecting supports 170 or deflection abatement structure, members 194are shown projecting across removed region 132 in a spaced-apartconfiguration from the exterior surface 124 of the end plate.

[0097] It is also within the scope of the invention that enclosure 12may include stress and/or deflection abatement structures that extendinto compartment 18 as opposed to, or in addition to, correspondingstructures that extend from the exterior surface of the end plates. InFIGS. 28-30, end plates 60 are shown illustrating examples of thesestructures. For example, in FIG. 28, end plate 60 includes a removedregion 132 that extends into the end plate from the interior surface 122of the end plate. It should be understood that region 132 may have anyof the configurations described, illustrated and/or incorporated hereinwith respect to removed regions that extend from the exterior surface ofa base plate. Similarly, in dashed lines at 170 in FIG. 28, supports areshown extending across region 132 to provide additional support and/orrigidity to the end plate. In FIG. 29, end plate 60 includes internalsupports 196 that are adapted to extend into compartment 18 tointerconnect the end plate with the corresponding end plate at the otherend of the compartment. As discussed, guide structures 144 may form sucha support. In FIG. 30, an internally projecting truss assembly 162 isshown.

[0098] Although not required or essential to the invention, in someembodiments, device 10 includes end plates 60 that exhibit at least oneof the following properties or combinations of properties compared to anend plate formed from a solid slab of uniform thickness of same materialas end plate 60 and exposed to the same operating parameters:

[0099] a projecting truss assembly;

[0100] an internally projecting support;

[0101] an externally projecting support;

[0102] an external removed region;

[0103] an internal removed region;

[0104] an integral shell portion;

[0105] an integral shell;

[0106] a reduced mass and reduced maximum stress;

[0107] a reduced mass and reduced maximum displacement;

[0108] a reduced mass and reduced perimeter displacement;

[0109] a reduced mass and increased heat transfer area;

[0110] a reduced mass and internally projecting supports;

[0111] a reduced mass and externally projecting supports;

[0112] a reduced maximum stress and reduced maximum displacement;

[0113] a reduced maximum stress and reduced perimeter displacement;

[0114] a reduced maximum stress and increased heat transfer area;

[0115] a reduced maximum stress and a projecting truss assembly;

[0116] a reduced maximum stress and a removed region;

[0117] a reduced maximum displacement and reduced perimeterdisplacement;

[0118] a reduced maximum displacement and increased heat transfer area;

[0119] a reduced perimeter displacement and increased heat transferarea;

[0120] a reduced perimeter displacement and a projecting truss assembly;

[0121] a reduced perimeter displacement and a removed region;

[0122] a mass/maximum displacement ratio that is less than 1500 lb/psi;

[0123] a mass/maximum displacement ratio that is less than 1000 lb/psi;

[0124] a mass/maximum displacement ratio that is less than 750 lb/psi;

[0125] a mass/maximum displacement ratio that is less than 500 lb/psi;

[0126] a mass/perimeter displacement ratio that is less than 2000lb/psi;

[0127] a mass/perimeter displacement ratio that is less than 1500lb/psi;

[0128] a mass/perimeter displacement ratio that is less than 1000lb/psi;

[0129] a mass/perimeter displacement ratio that is less than 800 lb/psi;

[0130] a mass/perimeter displacement ratio that is less than 600 lb/psi;

[0131] a cross-sectional area/mass ratio that is at least 6 in²/pound;

[0132] a cross-sectional area/mass ratio that is at least 7 in²/pound;and/or

[0133] a cross-sectional area/mass ratio that is at least 10 in²/pound.

[0134] As discussed, enclosure 12 contains an internal compartment 18that houses separation assembly 20, such as one or more separationmembranes 46, which are supported within the enclosure by a suitablemount 52. In the illustrative examples shown in FIGS. 2 and 4, theseparation membranes 46 were depicted as independent planar or tubularmembranes. It is also within the scope of the invention that themembranes may be arranged in pairs that define permeate region 32therebetween. In such a configuration, the membrane pairs may bereferred to as a membrane envelope, in that they define a commonpermeate region 32 in the form of a harvesting conduit, or flow path,extending therebetween and from which hydrogen-rich stream 34 may becollected.

[0135] An example of a membrane envelope is shown in FIG. 31 andgenerally indicated at 200. It should be understood that the membranepairs may take a variety of suitable shapes, such as planar envelopesand tubular envelopes. Similarly, the membranes may be independentlysupported, such as with respect to an end plate or around a centralpassage. For purposes of illustration, the following description andassociated illustrations will describe the separation assembly asincluding one or more membrane envelopes 200. It should be understoodthat the membranes forming the envelope may be two separate membranes,or may be a single membrane folded, rolled or otherwise configured todefine two membrane regions, or surfaces, 202 with permeate surfaces 50that are oriented toward each other to define a conduit 204 therebetweenfrom which the hydrogen-rich permeate gas may be collected andwithdrawn. Conduit 204 may itself form permeate region 32, or a device10 according to the present invention may include a plurality ofmembrane envelopes 200 and corresponding conduits 204 that collectivelydefine permeate region 32.

[0136] To support the membranes against high feed pressures, a support54 is used. Support 54 should enable gas that permeates throughmembranes 46 to flow therethough. Support 54 includes surfaces 211against which the permeate surfaces 50 of the membranes are supported.In the context of a pair of membranes forming a membrane envelope,support 54 may also be described as defining harvesting conduit 204. Inconduit 204, permeated gas preferably may flow both transverse andparallel to the surface of the membrane through which the gas passes,such as schematically illustrated in FIG. 31. The permeate gas, which isat least substantially pure hydrogen gas, may then be harvested orotherwise withdrawn from the envelope to form hydrogen-rich stream 34.Because the membranes lie against the support, it is preferable that thesupport does not obstruct the flow of gas through the hydrogen-selectivemembranes. The gas that does not pass through the membranes forms one ormore byproduct streams 36, as schematically illustrated in FIG. 31.

[0137] An example of a suitable support 54 for membrane envelopes 200 isshown in FIG. 32 in the form of a screen structure 210. Screen structure210 includes plural screen members 212. In the illustrated embodiment,the screen members include a coarse mesh screen 214 sandwiched betweenfine mesh screens 216. It should be understood that the terms “fine” and“coarse” are relative terms. Preferably, the outer screen members areselected to support membranes 46 without piercing the membranes andwithout having sufficient apertures, edges or other projections that maypierce, weaken or otherwise damage the membrane under the operatingconditions with which device 10 is operated. Because the screenstructure needs to provide for flow of the permeated gas generallyparallel to the membranes, it is preferable to use a relatively courserinner screen member to provide for enhanced, or larger, parallel flowconduits. In other words, the finer mesh screens provide betterprotection for the membranes, while the coarser mesh screen providesbetter flow generally parallel to the membranes.

[0138] The screen members may be of similar or the same construction,and more or less screen members may be used than shown in FIG. 32.Preferably, support 54 is formed from a corrosion-resistant materialthat will not impair the operation of the hydrogen purification deviceand other devices with which device 10 is used. Examples of suitablematerials for metallic screen members include stainless steels, titaniumand alloys thereof, zirconium and alloys thereof, corrosion-resistantalloys, including Inconel™ alloys, such as 800H™, and Hastelloy™ alloys,and alloys of copper and nickel, such as Monel™. Hastelloy™ and Inconel™alloys are nickel-based alloys. Inconel™ alloys typically contain nickelalloyed with chromium and iron. Monel™ alloys typically are alloys ofnickel, copper, iron and manganese. Additional examples of structure forsupports 54 include porous ceramics, porous carbon, porous metal,ceramic foam, carbon foam, and metal foam, either alone, or incombination with one or more screen members 212. As another example,some or all of the screen members may be formed from expanded metalinstead of a woven mesh material.

[0139] During fabrication of the membrane envelopes, adhesive may beused to secure membranes 46 to the screen structure and/or to secure thecomponents of screen structure 210 together, as discussed in more detailin the above-incorporated U.S. patent application Ser. No. 09/812,499.For purposes of illustration, adhesive is generally indicated in dashedlines at 218 in FIG. 32. An example of a suitable adhesive is sold by 3Munder the trade name SUPER 77. Typically, the adhesive is at leastsubstantially, if not completely, removed after fabrication of themembrane envelope so as not to interfere with the permeability,selectivity and flow paths of the membrane envelopes. An example of asuitable method for removing adhesive from the membranes and/or screenstructures or other supports is by exposure to oxidizing conditionsprior to initial operation of device 10. The objective of the oxidativeconditioning is to bum out the adhesive without excessively oxidizingthe palladium-alloy membrane. A suitable procedure for such oxidizing isdisclosed in the above-incorporated patent application.

[0140] Supports 54, including screen structure 210, may include acoating 219 on the surfaces 71 that engage membranes 46, such asindicated in dash-dot lines in FIG. 32. Examples of suitable coatingsinclude aluminum oxide, tungsten carbide, tungsten nitride, titaniumcarbide, titanium nitride, and mixtures thereof. These coatings aregenerally characterized as being thermodynamically stable with respectto decomposition in the presence of hydrogen. Suitable coatings areformed from materials, such as oxides, nitrides, carbides, orintermetallic compounds, that can be applied as a coating and which arethermodynamically stable with respect to decomposition in the presenceof hydrogen under the operating parameters (temperature, pressure, etc.)under which the hydrogen purification device will be operated. Suitablemethods for applying such coatings to the screen or expanded metalscreen member include chemical vapor deposition, sputtering, thermalevaporation, thermal spraying, and, in the case of at least aluminumoxide, deposition of the metal (e.g., aluminum) followed by oxidation ofthe metal to give aluminum oxide. In at least some embodiments, thecoatings may be described as preventing intermetallic diffusion betweenthe hydrogen-selective membranes and the screen structure.

[0141] The hydrogen purification devices 10 described, illustratedand/or incorporated herein may include one or more membrane envelopes200, typically along with suitable input and output ports through whichthe mixed gas stream is delivered and from which the hydrogen-rich andbyproduct streams are removed. In some embodiments, the device mayinclude a plurality of membrane envelopes. When the separation assemblyincludes a plurality of membrane envelopes, it may include fluidconduits interconnecting the envelopes, such as to deliver a mixed gasstream thereto, to withdraw the hydrogen-rich stream therefrom, and/orto withdraw the gas that does not pass through the membranes from mixedgas region 30. When the device includes a plurality of membraneenvelopes, the permeate stream, byproduct stream, or both, from a firstmembrane envelope may be sent to another membrane envelope for furtherpurification. The envelope or plurality of envelopes and associatedports, supports, conduits and the like may be referred to as a membranemodule 220.

[0142] The number of membrane envelopes 200 used in a particular device10 depends to a degree upon the feed rate of mixed gas stream 24. Forexample, a membrane module 220 containing four envelopes 200 has proveneffective for a mixed gas stream delivered to device 10 at a flow rateof 20 liters/minute. As the flow rate is increased, the number ofmembrane envelopes may be increased, such as in a generally linearrelationship. For example, a device 10 adapted to receive mixed gasstream 24 at a flow rate of 30 liters/minute may preferably include sixmembrane envelopes. However, these exemplary numbers of envelopes areprovided for purposes of illustration, and greater or fewer numbers ofenvelopes may be used. For example, factors that may affect the numberof envelopes to be used include the hydrogen flux through the membranes,the effective surface area of the membranes, the flow rate of mixed gasstream 24, the desired purity of hydrogen-rich stream 34, the desiredefficiency at which hydrogen gas is removed from mixed gas stream 24,user preferences, the available dimensions of device 10 and compartment18, etc.

[0143] Preferably, but not necessarily, the screen structure andmembranes that are incorporated into a membrane envelope 200 includeframe members 230, or plates, that are adapted to seal, support and/orinterconnect the membrane envelopes. An illustrative example of suitableframe members 230 is shown in FIG. 33. As shown, screen structure 210fits within a frame member 230 in the form of a permeate frame 232. Thescreen structure and frame 232 may collectively be referred to as ascreen plate or permeate plate 234. When screen structure 210 includesexpanded metal members, the expanded metal screen members may either fitwithin permeate frame 232 or extend at least partially over the surfaceof the frame. Additional examples of frame members 230 includesupporting frames, feed plates and/or gaskets. These frames, gaskets orother support structures may also define, at least in part, the fluidconduits that interconnect the membrane envelopes in an embodiment ofseparation assembly 20 that contains two or more membrane envelopes.Examples of suitable gaskets are flexible graphite gaskets, includingthose sold under the trade name GRAFOIL™ by Union Carbide, althoughother materials may be used, such as depending upon the operatingconditions under which device 10 is used.

[0144] Continuing the above illustration of exemplary frame members 230,permeate gaskets 236 and 236′ are attached to permeate frame 232,preferably but not necessarily, by using another thin application ofadhesive. Next, membranes 46 are supported against screen structure 210and/or attached to screen structure 210 using a thin application ofadhesive, such as by spraying or otherwise applying the adhesive toeither or both of the membrane and/or screen structure. Care should betaken to ensure that the membranes are flat and firmly attached to thecorresponding screen member 212. Feed plates, or gaskets, 238 and 238′are optionally attached to gaskets 236 and 236′, such as by usinganother thin application of adhesive. The resulting membrane envelope200 is then positioned within compartment 18, such as by a suitablemount 52. Optionally, two or more membrane envelopes may be stacked orotherwise supported together within compartment 18.

[0145] As a further alternative, each membrane 46 may be fixed to aframe member 230, such as a metal frame 240, as shown in FIG. 34. If so,the membrane is fixed to the frame, for instance by ultrasonic weldingor another suitable attachment mechanism. The membrane-frame assemblymay, but is not required to be, attached to screen structure 210 usingadhesive. Other examples of attachment mechanisms that achieve gas-tightseals between plates forming membrane envelope 200, as well as betweenthe membrane envelopes, include one or more of brazing, gasketing, andwelding. The membrane and attached frame may collectively be referred toas a membrane plate 242. It is within the scope of the invention thatthe various frames discussed herein do not all need to be formed fromthe same materials and/or that the frames may not have the samedimensions, such as the same thicknesses. For example, the permeate andfeed frames may be formed from stainless steel or another suitablestructural member, while the membrane plate may be formed from adifferent material, such as copper, alloys thereof, and other materialsdiscussed in the above-incorporated patents and applications.Additionally and/or alternatively, the membrane plate may, but is notrequired to be, thinner than the feed and/or permeate plates.

[0146] For purposes of illustration, a suitable geometry of fluid flowthrough membrane envelope 200 is described with respect to theembodiment of envelope 200 shown in FIG. 33. As shown, mixed gas stream24 is delivered to the membrane envelope and contacts the outer surfaces50 of membranes 46. The hydrogen-rich gas that permeates through themembranes enters harvesting conduit 204. The harvesting conduit is influid communication with conduits 250 through which the permeate streammay be withdrawn from the membrane envelope. The portion of the mixedgas stream that does not pass through the membranes flows to a conduit252 through which this gas may be withdrawn as byproduct stream 36. InFIG. 33, a single byproduct conduit 252 is shown, while in FIG. 34 apair of conduits 252 are shown to illustrate that any of the conduitsdescribed herein may alternatively include more than one fluid passage.It should be understood that the arrows used to indicate the flow ofstreams 34 and 36 have been schematically illustrated, and that thedirection of flow through conduits 250 and 252 may vary, such asdepending upon the configuration of a particular membrane envelope 200,module 220 and/or device 10.

[0147] In FIG. 35, another example of a suitable membrane envelope 200is shown. To graphically illustrate that end plates 60 and shell 62 mayhave a variety of configurations, envelope 200 is shown having agenerally rectangular configuration. The envelope of FIG. 35 alsoprovides another example of a membrane envelope having a pair ofbyproduct conduits 252 and a pair of hydrogen conduits 250. As shown,envelope 200 includes feed, or spacer, plates 238 as the outer mostframes in the envelope. Generally, each of plates 238 includes a frame260 that defines an inner open region 262. Each inner open region 262couples laterally to conduits 252. Conduits 250, however, are closedrelative to open region 262, thereby isolating hydrogen-rich stream 34.Membrane plates 242 lie adjacent and interior to plates 238. Membraneplates 242 each include as a central portion thereof ahydrogen-selective membrane 46, which may be secured to an outer frame240, which is shown for purposes of graphical illustration. In plates242, all of the conduits are closed relative to membrane 46. Eachmembrane lies adjacent to a corresponding one of open regions 262, i.e.,adjacent to the flow of mixed gas arriving to the envelope. Thisprovides an opportunity for hydrogen gas to pass through the membrane,with the non-permeating gases, i.e., the gases forming byproduct stream36, leaving open region 262 through conduit 252. Screen plate 234 ispositioned intermediate membranes 46 and/or membrane plates 242, i.e.,on the interior or permeate side of each of membranes 46. Screen plate234 includes a screen structure 210 or another suitable support 54.Conduits 252 are closed relative to the central region of screen plate234, thereby isolating the byproduct stream 36 and mixed gas stream 24from hydrogen-rich stream 34. Conduits 250 are open to the interiorregion of screen plate 234. Hydrogen gas, having passed through theadjoining membranes 46, travels along and through screen structure 210to conduits 250 and eventually to an output port as the hydrogen-richstream 34.

[0148] As discussed, device 10 may include a single membrane 46 withinshell 62, a plurality of membranes within shell 62, one or more membraneenvelopes 200 within shell 62 and/or other separation assemblies 20. InFIG. 36, a membrane envelope 200 similar to that shown in FIG. 34 isshown positioned within shell 62 to illustrate this point. It should beunderstood that envelope 200 may also schematically represent a membranemodule 220 containing a plurality of membrane envelopes, and/or a singlemembrane plate 242. Also shown for purposes of illustration is anexample of a suitable position for guide structures 144. As discussed,structures 144 also represent an example of internal supports 196. FIG.36 also illustrates graphically an example of suitable positions forports 64-68. To further illustrate suitable positions of the membraneplates and/or membrane envelopes within devices 10 containing end platesaccording to the present invention, FIGS. 37 and 38 respectivelyillustrate in dashed lines a membrane plate 242, membrane envelope 200and/or membrane module 220 positioned within a device 10 that includesthe end plates shown in FIGS. 13-14 and 21-25.

[0149] Shell 62 has been described as interconnecting the end plates todefine therewith internal compartment 18. It is within the scope of theinvention that the shell may be formed from a plurality ofinterconnected plates 230. For example, a membrane module 220 thatincludes one or more membrane envelopes 200 may form shell 62 becausethe perimeter regions of each of the plates may form a fluid-tight, orat least substantially fluid-tight seal therebetween. An example of sucha construction is shown in FIG. 39, in which a membrane module 220 thatincludes three membrane envelopes 200 is shown. It should be understoodthat the number of membrane envelopes may vary, from a single envelopeor even a single membrane plate 242, to a dozen or more. In FIG. 39, endplates 60 are schematically represented as having generally rectangularconfigurations to illustrate that configurations other than circularconfigurations are within the scope of the invention. It should beunderstood that the schematically depicted end plates 60 may have any ofthe end plate configurations discussed, illustrated and/or incorporatedherein.

[0150] In the preceding discussion, illustrative examples of suitablematerials of construction and methods of fabrication for the componentsof hydrogen purification devices according to the present invention havebeen discussed. It should be understood that the examples are not meantto represent an exclusive, or closed, list of exemplary materials andmethods, and that it is within the scope of the invention that othermaterials and/or methods may be used. For example, in many of the aboveexamples, desirable characteristics or properties are presented toprovide guidance for selecting additional methods and/or materials. Thisguidance is also meant as an illustrative aid, as opposed to recitingessential requirements for all embodiments.

[0151] As discussed, in embodiments of device 10 that include aseparation assembly that includes hydrogen-permeable and/orhydrogen-selective membranes 46, suitable materials for membranes 46include palladium and palladium alloys. As also discussed, the membranesmay be supported by frames and/or supports, such as the previouslydescribed frames 240, supports 54 and screen structure 210. Furthermore,devices 10 are often operated at selected operating parameters thatinclude elevated temperatures and pressures. In such an application, thedevices typically begin at a startup, or initial, operating state, inwhich the devices are typically at ambient temperature and pressure,such as atmospheric pressure and a temperature of approximately 25° C.From this state, the device is heated (such as with heating assembly 42)and pressurized (via any suitable mechanism) to selected operatingparameters, such as temperatures of 200° C. or more, and selectedoperating pressures, such as pressure of 50 psi or more.

[0152] When devices 10 are heated, the components of the devices willexpand. The degree to which the components enlarge or expand is largelydefined by the coefficient of thermal expansion (CTE) of the materialsfrom which the components are formed. Accordingly, these differences inCTEs will tend to cause the components to expand at different rates,thereby placing additional tension or compression on some componentsand/or reduced tension or compression on others.

[0153] For example, consider a hydrogen-selective membrane 46 formedfrom an alloy of 60 wt % palladium and 40 wt % copper (Pd-40 Cu). Such amembrane has a coefficient of thermal expansion of 14.9 (μm/m)/° C.Further consider that the membrane is secured to a structural frame 230or other mount, or retained against a support 54 formed from a materialhaving a different CTE than Pd-40 Cu or another material from whichmembrane 46 is formed. When a device 10 in which these components areoperated is heated from an ambient or resting configuration, thecomponents will expand at different rates. Typically, device 10 isthermally cycled within a temperature range of at least 200° C., andoften within a range of at least 250° C., 300° C. or more. If the CTE ofthe membrane is less than the CTE of the adjoining structural component,then the membrane will tend to be stretched as the components areheated.

[0154] In addition to this initial stretching, it should be consideredthat hydrogen purification devices typically experience thermal cyclingas they are heated for use, then cooled or allowed to cool when not inuse, then reheated, recooled, etc. In such an application, the stretchedmembrane may become wrinkled as it is compressed toward its originalconfiguration as the membrane and other structural component(s) arecooled.

[0155] On the other hand, if the CTE of the membrane is greater than theCTE of the adjoining structural component, then the membrane will tendto be compressed during heating of the device, and this compression maycause wrinkling of the membrane. During cooling, or as the componentscool, the membrane is then drawn back to its original configuration.

[0156] As an illustrative example, consider membrane plate 242 shown inFIG. 34. If the CTE of membrane 46 is greater than the CTE of framemember 230, which typically has a different composition than membrane46, then the membrane will tend to expand faster when heated than theframe. Accordingly, compressive forces will be imparted to the membranefrom frame 230, and these forces may produce wrinkles in the membrane.In contrast, if the CTE of membrane 46 is less than the CTE of frame230, then the frame will expand faster when heated than membrane 46. Asthis occurs, expansive forces will be imparted to the membrane, as theexpansion of the frame in essence tries to stretch the membrane. Whileneither of these situations is desirable, compared to an embodiment inwhich the frame and membrane have the same or essentially the same CTE,the former scenario may in some embodiments be the more desirable of thetwo because it may be less likely to produce wrinkles in the membrane.

[0157] Wrinkling of membrane 46 may cause holes and cracks in themembrane, especially along the wrinkles where the membrane is fatigued.In regions where two or more wrinkles intersect, the likelihood of holesand/or cracks is increased because that portion of the membrane has beenwrinkled in at least two different directions. It should be understoodthat holes and cracks lessen the selectivity of the membrane forhydrogen gas because the holes and/or cracks are not selective forhydrogen gas and instead allow any of the components of the mixed gasstream to pass thereto. During repeated thermal cycling of the membrane,these points or regions of failure will tend to increase in size,thereby further decreasing the purity of the hydrogen-rich, or permeate,stream. It should be further understood that these wrinkles may becaused by forces imparted to the membrane from portions of device 10that contact the membrane directly, and which accordingly may bereferred to as membrane-contacting portions or structure, or by otherportions of the device that do not contact the membrane but which uponexpansion and/or cooling impart forces that are transmitted to themembrane. Examples of membrane-contacting structure include frames orother mounts 52 and supports 54 upon which the membrane is mounted orwith which membrane 46 is in contact even if the membrane is notactually secured or otherwise mounted thereon. Examples of portions ofdevice 10 that may, at least in some embodiments, impartwrinkle-inducing forces to membrane 46 include the enclosure 12, andportions thereof such as one or more end plates 60 and/or shell 62.Other examples include gaskets and spacers between the end plates andthe frames or other mounts for the membrane, and in embodiments ofdevice 10 that include a plurality of membranes, between adjacent framesor other supports or mounts for the membranes.

[0158] One approach to guarding against membrane failure due todifferences in CTE between the membranes and adjoining structuralcomponents is to place deformable gaskets between the membrane and anycomponent of device 10 that contacts the membrane and has sufficientstiffness or structure to impart compressive or tensile forces to themembrane that may wrinkle the membrane. For example, in FIG. 33,membrane 46 is shown sandwiched between feed plate 238 and permeategasket 236, both of which may be formed from a deformable material. Insuch an embodiment and with such a construction, the deformable gasketsbuffer, or absorb, at least a significant portion of the compressive ortensile forces that otherwise would be exerted upon membrane 46.

[0159] In embodiments where either or both of these frames are notformed from a deformable material (i.e., a resilient material that maybe compressed or expanded as forces are imparted thereto and whichreturns to its original configuration upon removal of those forces),when membrane 46 is mounted on a plate 242 that has a thickness and/orcomposition that may exert the above-described wrinkling tensile orcompressive forces to membrane 46, or when support 54 is bonded (orsecured under the selected operating pressure) to membrane 46, adifferent approach may additionally or alternatively be used. Morespecifically, the life of the membranes may be increased by formingcomponents of device 10 that otherwise would impart wrinkling forces,either tensile or compressive, to membrane 46 from materials having aCTE that is the same or similar to that of the material or materialsfrom which membrane 46 is formed.

[0160] For example, Type 304 stainless steel has a CTE of 17.3 and Type316 stainless steel has a CTE of 16.0. Accordingly, Type 304 stainlesssteel has a CTE that is approximately 15% greater than that of Pd-40 Cu,and Type 316 stainless steel has a CTE that is approximately 8% greaterthan that of Pd-40 Cu. This does not mean that these materials may notbe used to form the various supports, frames, plates, shells and thelike discussed herein. However, in some embodiments of the invention, itmay be desirable to form at least some of these components from amaterial that has a CTE that is the same as or more similar to that ofthe material from which membrane 46 is formed. More specifically, it maybe desirable to have a CTE that is the same as the CTE of the materialfrom which membrane 46 is formed, or a material that has a CTE that iswithin a selected range of the CTE of the material from which membrane46 is selected, such as within ±0.5%, 1%, 2%, 5%, 10%, or 15%. Expressedanother way, in at least some embodiments, it may be desirable to formthe membrane-contacting portions or other elements of the enclosure froma material or materials have a CTE that is within ±1.2, 1, 0.5, 0.2, 0.1or less than 0.1 μm/m/° C. of the CTE from which membrane 46 is at leastsubstantially formed.

[0161] In the following table, exemplary alloys and their correspondingCTE's and compositions are presented. It should be understood that thematerials listed in the following table are provided for purposes ofillustration, and that other materials may be used, includingcombinations of the below-listed materials and/or other materials,without departing from the scope of the invention. TABLE 1 Alloy CTENominal Composition Type/Grade (μm/m/C) C Mn Ni Cr Co Mo W Nb Cu Ti AlFe Si Pd-40Cu 14.9 Monel 400 13.9 .02 1.5 65 32 2.0 (UNS N04400) Monel401 13.7 .05 2.0 42 54 0.5 (UNS N04401) Monel 405 13.7 .02 1.5 65 32 2.0(UNS N04405) Monel 500 13.7 .02 1.0 65 32 0.6 1.5 (UNS N05500) Type 30417.3 .05 1.5 9.0 19.0 Bal 0.5 Stainless (UNS S30400) Type 316 16.0 .051.5 12.0 17.0 2.5 Bal 0.5 Stainless (UNS S31600) Type 310S 15.9 .05 1.520.5 25.0 Bal 1.1 Stainless (UNS S31008) Type 330 14.4 .05 1.5 35.5 18.5Bal 1.1 Stainless (UNS N08330) AISI Type 14.0 .1 1.5 20.0 21.0 20.5 3.02.5 1.0 31.0 0.8 661 Stainless (UNS R30155) Inconel 600 13.3 .08 76.015.5 8.0 (UNS N06600) Inconel 601 13.75 .05 60.5 23.0 0.5 1.35 14.1 (UNSN06601) Inconel 625 12.8 .05 61.0 21.5 9.0 3.6 0.2 0.2 2.5 (UNS N06625)Incoloy 800 14.4 .05 0.8 32.5 0.4 0.4 0.4 46.0 0.5 (UNS N08800) Nimonic13.5 .05 42.5 12.5 6.0 2.7 36.2 Alloy 901 (UNS N09901) Hastelloy X 13.3.15 49.0 22.0 1.5 9.0 0.6 2 15.8 (UNS N06002) Inconel 718 13.0 .05 52.519.0 3.0 5.1 0.9 0.5 18.5 UNS N07718) Haynes 230 12.7 0.1 55.0 22.0 5.02.0 14 0.35 3.0 (UNS N06002)

[0162] From the above information, it can be seen that alloys such asType 330 stainless steel and Incoloy 800 have CTEs that are withinapproximately 3% of the CTE of Pd40 Cu, and Monel 400 and Types 310Sstainless steel have CTEs that deviate from the CTE of Pd40 Cu by lessthan 7%.

[0163] To illustrate that the selection of materials may vary with theCTE of the particular membrane being used, consider a material formembrane 46 that has a coefficient of thermal expansion of 13.8 μm/m/°C. From the above table, it can be seen that the Monel and Inconel 600alloys have CTE's that deviate, or differ from, the CTE of the membraneby 0.1 μm/m/° C. As another example, consider a membrane having a CTE of13.4 μm/m/° C. Hastelloy X has a CTE that corresponds to that of themembrane, and that the Monel and Inconel 601 alloys have CTE's that arewithin approximately 1% of the CTE of the membrane. Of the illustrativeexample of materials listed in the table, all of the alloys other thanHastelloy X, Incoloy 800 and the Type 300 series of stainless steelalloys have CTE's that are within 2% of the CTE of the membrane, and allof the alloys except Type 304, 316 and 310S stainless steel alloys haveCTE's that are within 5% of the CTE of the membrane.

[0164] Examples of components of device 10 that may be formed from amaterial having a selected CTE relative to membrane 46, such as a CTEcorresponding to or within one of the selected ranges of the CTE ofmembrane 46, include one or more of the following: support 54, screenmembers 212, fine or outer screen or expanded metal member 216, innerscreen member 214, membrane frame 240, permeate frame 232, permeateplate 234, feed plate 238. By the above, it should be understood thatone of the above components may be formed from such a material, morethan one of the above components may be formed from such a material, butthat none of the above components are required to be formed from such amaterial. Similarly, the membranes 46 may be formed from materials otherthan Pd-40 Cu, and as such the selected CTE's will vary depending uponthe particular composition of membranes 46.

[0165] By way of further illustration, a device 10 may be formed with amembrane module 220 that includes one or more membrane envelopes 200with a screen structure that is entirely formed from a material havingone of the selected CTE's; only outer, or membrane-contacting, screenmembers (such as members 216) formed from a material having one of theselected CTE's and the inner member or members being formed from amaterial that does not have one of the selected CTE'S; inner screenmember 214 formed from a material having one of the selected CTE's, withthe membrane-contacting members being formed from a material that doesnot have one of the selected CTE's, etc. By way of further illustration,a device 10 may have a single membrane 46 supported between the endplates 60 of the enclosure by one or more mounts 52 and/or one or moresupports 54. The mounts and/or the supports may be formed from amaterial having one of the selected CTE's. Similarly, at least a portionof enclosure 12, such as one or both of end plates 60 or shell 62, maybe formed from a material having one of the selected CTE's.

[0166] In embodiments of device 10 in which there are components of thedevice that do not directly contact membrane 46, these components maystill be formed from a material having one of the selected CTE's. Forexample, a portion or all of enclosure 12, such as one or both of endplates 60 or shell 62, may be formed from a material, including one ofthe alloys listed in Table 1, having one of the selected CTE's relativeto the CTE of the material from which membrane 46 is formed even thoughthese portions do not directly contact membrane 46.

[0167] A hydrogen purification device 10 constructed according to thepresent invention may be coupled to, or in fluid communication with, anysource of impure hydrogen gas. Examples of these sources include gasstorage devices, such as hydride beds and pressurized tanks. Anothersource is an apparatus that produces as a byproduct, exhaust or wastestream a flow of gas from which hydrogen gas may be recovered. Stillanother source is a fuel processor, which as used herein, refers to anydevice that is adapted to produce a mixed gas stream containing hydrogengas from at least one feed stream containing a feedstock. Typically,hydrogen gas will form a majority or at least a substantial portion ofthe mixed gas stream produced by a fuel processor.

[0168] A fuel processor may produce mixed gas stream 24 through avariety of mechanisms. Examples of suitable mechanisms include steamreforming and autothermal reforming, in which reforming catalysts areused to produce hydrogen gas from a feed stream containing acarbon-containing feedstock and water. Other suitable mechanisms forproducing hydrogen gas include pyrolysis and catalytic partial oxidationof a carbon-containing feedstock, in which case the feed stream does notcontain water. Still another suitable mechanism for producing hydrogengas is electrolysis, in which case the feedstock is water. Examples ofsuitable carbon-containing feedstocks include at least one hydrocarbonor alcohol. Examples of suitable hydrocarbons include methane, propane,natural gas, diesel, kerosene, gasoline and the like. Examples ofsuitable alcohols include methanol, ethanol, and polyols, such asethylene glycol and propylene glycol.

[0169] A hydrogen purification device 10 adapted to receive mixed gasstream 24 from a fuel processor is shown schematically in FIG. 40. Asshown, the fuel processor is generally indicated at 300, and thecombination of a fuel processor and a hydrogen purification device maybe referred to as a fuel processing system 302. Also shown in dashedlines at 42 is a heating assembly, which as discussed provides heat todevice 10 and may take a variety of forms. Fuel processor 300 may takeany of the forms discussed above. To graphically illustrate that ahydrogen purification device according to the present invention may alsoreceive mixed gas stream 24 from sources other than a fuel processor300, a gas storage device is schematically illustrated at 306 and anapparatus that produces mixed gas stream 24 as a waste or byproductstream in the course of producing a different product stream 308 isshown at 310. It should be understood that the schematic representationof fuel processor 300 is meant to include any associated heatingassemblies, feedstock delivery systems, air delivery systems, feedstream sources or supplies, etc.

[0170] Fuel processors are often operated at elevated temperaturesand/or pressures. As a result, it may be desirable to at least partiallyintegrate hydrogen purification device 10 with fuel processor 300, asopposed to having device 10 and fuel processor 300 connected by externalfluid transportation conduits. An example of such a configuration isshown in FIG. 42, in which the fuel processor includes a shell orhousing 312, which device 10 forms a portion of and/or extends at leastpartially within. In such a configuration, fuel processor 300 may bedescribed as including device 10. Integrating the fuel processor orother source of mixed gas stream 24 with hydrogen purification device 10enables the devices to be more easily moved as a unit. It also enablesthe fuel processor's components, including device 10, to be heated by acommon heating assembly and/or for at least some if not all of theheating requirements of device 10 be to satisfied by heat generated byprocessor 300.

[0171] As discussed, fuel processor 300 is any suitable device thatproduces a mixed gas stream containing hydrogen gas, and preferably amixed gas stream that contains a majority of hydrogen gas. For purposesof illustration, the following discussion will describe fuel processor300 as being adapted to receive a feed stream 316 containing acarbon-containing feedstock 318 and water 320, as shown in FIG. 42.However, it is within the scope of the invention that the fuel processor300 may take other forms, as discussed above, and that feed stream 316may have other compositions, such as containing only a carbon-containingfeedstock or only water.

[0172] Feed stream 316 may be delivered to fuel processor 300 via anysuitable mechanism. A single feed stream 316 is shown in FIG. 42, but itshould be understood that more than one stream 316 may be used and thatthese streams may contain the same or different components. When thecarbon-containing feedstock 318 is miscible with water, the feedstock istypically delivered with the water component of feed stream 316, such asshown in FIG. 42. When the carbon-containing feedstock is immiscible oronly slightly miscible with water, these components are typicallydelivered to fuel processor 300 in separate streams, such as shown indashed lines in FIG. 42. In FIG. 42, feed stream 316 is shown beingdelivered to fuel processor 300 by a feed stream delivery system 317.Delivery system 317 includes any suitable mechanism, device, orcombination thereof that delivers the feed stream to fuel processor 300.For example, the delivery system may include one or more pumps thatdeliver the components of stream 316 from a supply. Additionally, oralternatively, system 317 may include a valve assembly adapted toregulate the flow of the components from a pressurized supply. Thesupplies may be located external of the fuel cell system, or may becontained within or adjacent the system.

[0173] As generally indicated at 312 in FIG. 42, fuel processor 300includes a hydrogen-producing region in which mixed gas stream 24 isproduced from feed stream 316. As discussed, a variety of differentprocesses may be utilized in hydrogen-producing region. An example ofsuch a process is steam reforming, in which region 312 includes a steamreforming catalyst 334. Alternatively, region 312 may produce stream 24by autothermal reforming, in which case region 312 includes anautothermal reforming catalyst. In the context of a steam or autothermalreformer, mixed gas stream 24 may also be referred to as a reformatestream. Preferably, the fuel processor is adapted to producesubstantially pure hydrogen gas, and even more preferably, the fuelprocessor is adapted to produce pure hydrogen gas. For the purposes ofthe present invention, substantially pure hydrogen gas is greater than90% pure, preferably greater than 95% pure, more preferably greater than99% pure, and even more preferably greater than 99.5% pure. Examples ofsuitable fuel processors are disclosed in U.S. Pat. No. 6,221,117,pending U.S. patent application Ser. No. 09/802,361, which was filed onMar. 8, 2001, and is entitled “Fuel Processor and Systems and DevicesContaining the Same,” and pending U.S. patent application Ser. No.09/812,499, which was filed on Mar. 19, 2001, and is entitled“Hydrogen-Selective Metal Membrane Modules and Method of Forming theSame,” each of which is incorporated by reference in its entirety forall purposes.

[0174] Fuel processor 300 may, but does not necessarily, further includea polishing region 348, such as shown in dashed lines in FIG. 42.Polishing region 348 receives hydrogen-rich stream 34 from device 10 andfurther purifies the stream by reducing the concentration of, orremoving, selected compositions therein. In FIG. 42, the resultingstream is indicated at 314 and may be referred to as a product hydrogenstream or purified hydrogen stream. When fuel processor 300 does notinclude polishing region 348, hydrogen-rich stream 34 forms producthydrogen stream 314. For example, when stream 34 is intended for use ina fuel cell stack, compositions that may damage the fuel cell stack,such as carbon monoxide and carbon dioxide, may be removed from thehydrogen-rich stream, if necessary. The concentration of carbon monoxideshould be less than 10 ppm (parts per million) to prevent the controlsystem from isolating the fuel cell stack. Preferably, the system limitsthe concentration of carbon monoxide to less than 5 ppm, and even morepreferably, to less than 1 ppm. The concentration of carbon dioxide maybe greater than that of carbon monoxide. For example, concentrations ofless than 25% carbon dioxide may be acceptable. Preferably, theconcentration is less than 10%, even more preferably, less than 1%.Especially preferred concentrations are less than 50 ppm. It should beunderstood that the acceptable minimum concentrations presented hereinare illustrative examples, and that concentrations other than thosepresented herein may be used and are within the scope of the presentinvention. For example, particular users or manufacturers may requireminimum or maximum concentration levels or ranges that are differentthan those identified herein.

[0175] Region 348 includes any suitable structure for removing orreducing the concentration of the selected compositions in stream 34.For example, when the product stream is intended for use in a PEM fuelcell stack or other device that will be damaged if the stream containsmore than determined concentrations of carbon monoxide or carbondioxide, it may be desirable to include at least one methanationcatalyst bed 350. Bed 350 converts carbon monoxide and carbon dioxideinto methane and water, both of which will not damage a PEM fuel cellstack. Polishing region 348 may also include another hydrogen-producingregion 352, such as another reforming catalyst bed, to convert anyunreacted feedstock into hydrogen gas. In such an embodiment, it ispreferable that the second reforming catalyst bed is upstream from themethanation catalyst bed so as not to reintroduce carbon dioxide orcarbon monoxide downstream of the methanation catalyst bed.

[0176] Steam reformers typically operate at temperatures in the range of200° C. and 700° C., and at pressures in the range of 50 psi and 1000psi, although temperatures outside of this range are within the scope ofthe invention, such as depending upon the particular type andconfiguration of fuel processor being used. Any suitable heatingmechanism or device may be used to provide this heat, such as a heater,burner, combustion catalyst, or the like. The heating assembly may beexternal the fuel processor or may form a combustion chamber that formspart of the fuel processor. The fuel for the heating assembly may beprovided by the fuel processing or fuel cell system, by an externalsource, or both.

[0177] In FIG. 42, fuel processor 300 is shown including a shell 312 inwhich the above-described components are contained. Shell 312, whichalso may be referred to as a housing, enables the components of the fuelprocessor to be moved as a unit. It also protects the components of thefuel processor from damage by providing a protective enclosure andreduces the heating demand of the fuel processor because the componentsof the fuel processor may be heated as a unit. Shell 312 may, but doesnot necessarily, include insulating material 333, such as a solidinsulating material, blanket insulating material, or an air-filledcavity. It is within the scope of the invention, however, that the fuelprocessor may be formed without a housing or shell. When fuel processor300 includes insulating material 333, the insulating material may beinternal the shell, external the shell, or both. When the insulatingmaterial is external a shell containing the above-described reforming,separation and/or polishing regions, the fuel processor may furtherinclude an outer cover or jacket external the insulation.

[0178] It is further within the scope of the invention that one or moreof the components of fuel processor 300 may either extend beyond theshell or be located external at least shell 312. For example, device 10may extend at least partially beyond shell 312, as indicated in FIG. 41.As another example, and as schematically illustrated in FIG. 42,polishing region 348 may be external shell 312 and/or a portion ofhydrogen-producing region 312 (such as portions of one or more reformingcatalyst beds) may extend beyond the shell.

[0179] As indicated above, fuel processor 300 may be adapted to deliverhydrogen-rich stream 34 or product hydrogen stream 314 to at least onefuel cell stack, which produces an electric current therefrom. In such aconfiguration, the fuel processor and fuel cell stack may be referred toas a fuel cell system. An example of such a system is schematicallyillustrated in FIG. 43, in which a fuel cell stack is generallyindicated at 322. The fuel cell stack is adapted to produce an electriccurrent from the portion of product hydrogen stream 314 deliveredthereto. In the illustrated embodiment, a single fuel processor 300 anda single fuel cell stack 322 are shown and described, however, it shouldbe understood that more than one of either or both of these componentsmay be used. It should also be understood that these components havebeen schematically illustrated and that the fuel cell system may includeadditional components that are not specifically illustrated in thefigures, such as feed pumps, air delivery systems, heat exchangers,heating assemblies and the like.

[0180] Fuel cell stack 322 contains at least one, and typicallymultiple, fuel cells 324 that are adapted to produce an electric currentfrom the portion of the product hydrogen stream 314 delivered thereto.This electric current may be used to satisfy the energy demands, orapplied load, of an associated energy-consuming device 325. Illustrativeexamples of devices 325 include, but should not be limited to, a motorvehicle, recreational vehicle, boat, tools, lights or lightingassemblies, appliances (such as a household or other appliance),household, signaling or communication equipment, etc. It should beunderstood that device 325 is schematically illustrated in FIG. 43 andis meant to represent one or more devices or collection of devices thatare adapted to draw electric current from the fuel cell system. A fuelcell stack typically includes multiple fuel cells joined togetherbetween common end plates 323, which contain fluid delivery/removalconduits (not shown). Examples of suitable fuel cells include protonexchange membrane (PEM) fuel cells and alkaline fuel cells. Fuel cellstack 322 may receive all of product hydrogen stream 314. Some or all ofstream 314 may additionally, or alternatively, be delivered, via asuitable conduit, for use in another hydrogen-consuming process, burnedfor fuel or heat, or stored for later use.

Industrial Applicability

[0181] The invented hydrogen purification devices, components and fuelprocessing systems are applicable to the fuel processing and otherindustries in which hydrogen gas is produced and/or utilized.

[0182] It is believed that the disclosure set forth above encompassesmultiple distinct inventions with independent utility. While each ofthese inventions has been disclosed in its preferred form, the specificembodiments thereof as disclosed and illustrated herein are not to beconsidered in a limiting sense as numerous variations are possible. Thesubject matter of the inventions includes all novel and non-obviouscombinations and subcombinations of the various elements, features,functions and/or properties disclosed herein. Similarly, where theclaims recite “a” or “a first” element or the equivalent thereof, suchclaims should be understood to include incorporation of one or more suchelements, neither requiring nor excluding two or more such elements.

[0183] It is believed that the following claims particularly point outcertain combinations and subcombinations that are directed to one of thedisclosed inventions and are novel and non-obvious. Inventions embodiedin other combinations and subcombinations of features, functions,elements and/or properties may be claimed through amendment of thepresent claims or presentation of new claims in this or a relatedapplication. Such amended or new claims, whether they are directed to adifferent invention or directed to the same invention, whetherdifferent, broader, narrower or equal in scope to the original claims,are also regarded as included within the subject matter of theinventions of the present disclosure.

We claim:
 1. A fuel processor, comprising: a hydrogen-producing regionadapted to receive a feed stream and to produce a mixed gas streamcontaining hydrogen gas and other gases from the feed stream; aseparation region adapted to receive at least a portion of the mixed gasstream and to produce therefrom a hydrogen-rich stream containing atleast substantially hydrogen gas, wherein the separation regioncomprises: an enclosure defining an internal compartment, wherein theenclosure includes at least one input port through which a mixed gasstream containing hydrogen gas is delivered to the enclosure, at leastone product output port through which a permeate stream containing atleast substantially pure hydrogen gas is removed from the enclosure, andat least one byproduct output port through which a byproduct streamcontaining at least a substantial portion of the other gases is removedfrom the enclosure, wherein the hydrogen-rich stream includes at least aportion of the permeate stream; a hydrogen-selective membrane within thecompartment, wherein the hydrogen-selective membrane has a coefficientof thermal expansion, a first surface adapted to be contacted by themixed gas stream, a permeate surface generally opposed to the firstsurface, and is at least substantially formed from an alloy containingpalladium and copper, wherein the permeate stream includes a portion ofthe mixed gas stream that passes through the hydrogen-selective membraneto the permeate surface, and further wherein the byproduct streamincludes a portion of the mixed gas stream that does not pass throughthe hydrogen-selective membrane; and means for supporting thehydrogen-selective membrane within the enclosure, wherein the means forsupporting the hydrogen-selective membrane within the enclosure includesa membrane-contacting structure that is at least partially formed froman alloy that includes nickel and copper and which has a coefficient ofthermal expansion that is the same as or within at least approximately10% of the coefficient of thermal expansion of the hydrogen-selectivemembrane.
 2. The fuel processor of claim 1, wherein the coefficient ofthermal expansion of the membrane-contacting structure is within 5% ofthe coefficient of thermal expansion of the membrane.
 3. The fuelprocessor of claim 2, wherein the coefficient of thermal expansion ofthe membrane-contacting structure is within 2% of the coefficient ofthermal expansion of the membrane.
 4. The fuel processor of claim 1,wherein the coefficient of thermal expansion of the membrane-contactingstructure deviates from the coefficient of thermal expansion of themembrane by no more than approximately 1 μm/m/° C.
 5. The fuel processorof claim 4, wherein the coefficient of thermal expansion of themembrane-contacting structure deviates from the coefficient of thermalexpansion of the membrane by no more than approximately 0.2 μm/m/° C. 6.The fuel processor of claim 1, wherein the membrane-contacting structurehas a coefficient of thermal expansion that is less than 16 μm/m/° C.and greater than 13 μm/m/° C.
 7. The fuel processor of claim 1, whereinthe membrane-contacting structure has a coefficient of thermal expansionthat is less than the coefficient of thermal expansion of the membrane.8. The fuel processor of claim 1, wherein the means for supporting thehydrogen-selective membrane is at least substantially formed from analloy that includes nickel and copper.
 9. The fuel processor of claim 1,wherein the means for supporting the hydrogen-selective membrane is atleast substantially formed from one or more materials havingcoefficients of thermal expansion that are less than the coefficient ofthermal expansion of the membrane.
 10. The fuel processor of claim 1,wherein the membrane-contacting structure is not hydrogen-selective. 11.The fuel processor of claim 1, wherein the membrane is mounted on themembrane-contacting structure.
 12. The fuel processor of claim 1,wherein the membrane is in contact with but not mounted on themembrane-contacting structure.
 13. The fuel processor of claim 1,wherein the membrane-contacting structure includes a mount adapted toposition the membrane within the enclosure.
 14. The fuel processor ofclaim 13, wherein the mount is formed from a material that is nothydrogen-selective or hydrogen-permeable.
 15. The fuel processor ofclaim 13, wherein the membrane includes a perimeter region and the mountincludes a frame that is secured to the perimeter region of themembrane.
 16. The fuel processor of claim 15, wherein the frame forms aportion of the enclosure.
 17. The fuel processor of claim 15, whereinthe frame has a coefficient of thermal expansion that is the same as orless than the coefficient of thermal expansion of the membrane.
 18. Thefuel processor of claim 1, wherein the membrane-contacting structureincludes a support that extends across at least a substantial portion ofthe first surface or the permeate surface of the membrane.
 19. The fuelprocessor of claim 18, wherein the support has a coefficient of thermalexpansion that is the same as or less than the coefficient of thermalexpansion of the membrane.
 20. The fuel processor of claim 18, whereinthe support extends across at least a substantial portion of thepermeate surface of the membrane.
 21. The fuel processor of claim 20,wherein the permeate surface of the membrane is in contact with thesupport but is not mounted on the support, and further wherein theportion of the mixed gas stream that passes through the membrane maypass through the support.
 22. The fuel processor of claim 21, whereinthe support includes at least one screen structure.
 23. The fuelprocessor of claim 21, wherein the membrane is a firsthydrogen-selective membrane, wherein the enclosure further includes asecond hydrogen-selective membrane that has a coefficient of thermalexpansion that is at least substantially the same as the first membrane,a first surface adapted to be contacted by the mixed gas stream, and apermeate surface that generally faces the permeate surface of the firstmembrane, and further wherein the support extends between the first andthe second membranes to define a harvesting conduit between the permeatesurfaces of the membranes through which the portion of the mixed gasstream that passes through the membranes may flow.
 24. The fuelprocessor of claim 1, wherein the enclosure is at least partially formedfrom one or more materials having a coefficient of thermal expansionthat is at least substantially the same as or within at leastapproximately 10% of the coefficient of thermal expansion of themembrane.
 25. The fuel processor of claim 24, wherein the coefficient ofthermal expansion of the one or more materials is within 2% of thecoefficient of thermal expansion of the membrane.
 26. The fuel processorof claim 1, wherein the coefficient of thermal expansion of the one ormore materials is within 1 μm/m/° C. of the coefficient of thermalexpansion of the membrane.
 27. The fuel processor of claim 26, whereinthe enclosure includes an alloy containing nickel and copper.
 28. Thefuel processor of claim 1, wherein the membrane has a coefficient ofthermal expansion in the range of approximately 13.6 μm/m/° C. andapproximately 16 μm/m/° C.
 29. The fuel processor of claim 1, incombination with a fuel cell stack adapted to receive at least a portionof the permeate stream.
 30. The fuel processor of claim 1, wherein thefuel processor includes at least one reforming catalyst bed and isadapted to produce the mixed gas stream by steam reforming.
 31. The fuelprocessor of claim 30, wherein the reforming catalyst bed and theenclosure are at least partially housed within a common shell.
 32. Thefuel processor of claim 31, wherein the enclosure forms at least aportion of a shell in which the reforming catalyst bed is enclosed. 33.In a hydrogen purification device that is adapted to be operated at aselected temperature of at least 200° C. and a selected pressure of atleast 50 psi and which includes an enclosure with an internal, at leastsubstantially fluid-tight, compartment containing at least onehydrogen-selective membrane that has a coefficient of thermal expansion,is formed from an alloy of palladium and copper, includes a firstsurface adapted to be contacted by a mixed gas stream containinghydrogen gas and other gases, further includes a permeate surface, andis adapted to separate the mixed gas stream into a hydrogen-rich stream,which comprises at least substantially hydrogen gas and which is atleast partially formed from a portion of the mixed gas stream thatpasses through the at least one hydrogen-selective membrane, and abyproduct stream, which is at least partially formed from a portion ofthe mixed gas stream that does not pass through the membrane, theimprovement comprising: the device including a membrane-contactingstructure that is in contact with at least one of the first or thepermeate surfaces of the membrane, and further wherein the deviceincludes at least one membrane-contacting structure in contact with theat least one hydrogen-selective membrane and further wherein the atleast one membrane-contacting structure is selected to have acoefficient of thermal expansion that is sufficiently close to or equalto the coefficient of thermal expansion of the at least onehydrogen-selective membrane such that upon thermal cycling of the devicewithin a temperature range of at least 200° C. the at least onemembrane-contacting structure is adapted to not impart wrinkles to theat least one hydrogen-selective membrane.
 34. The device of claim 33,wherein the membrane-contacting structure includes an alloy comprisingnickel and copper.
 35. The device of claim 33, wherein themembrane-contacting structure has a coefficient of thermal expansionthat is the same as or less than the coefficient of thermal expansion ofthe at least one membrane.
 36. The device of claim 33, wherein theenclosure is formed from one or more materials selected such that uponthermal cycling of the device within the temperature range the enclosuredoes not impart wrinkle-inducing forces to the at least onehydrogen-selective membrane.
 37. The device of claim 36, wherein theenclosure includes an alloy comprising nickel and copper.
 38. The deviceof claim 37, wherein the enclosure has a coefficient of thermalexpansion that is the same as or less than the coefficient of thermalexpansion of the at least one membrane.
 39. The device of claim 33,wherein the alloy comprises approximately 40 wt % copper.
 40. The deviceof claim 33, in combination with a fuel processing assembly that isadapted to receive a feed stream and to produce the mixed gas streamtherefrom.
 41. The device of claim 40, wherein the fuel processingassembly includes at least one reforming catalyst bed and furtherwherein the feed stream contains water and a carbon-containingfeedstock.
 42. The device of claim 41, wherein the reforming region andthe enclosure are at least partially housed within a common shell. 43.The device of claim 40, in further combination with a fuel cell stackadapted to receive at least a portion of the hydrogen-rich stream and toproduce an electric current therefrom.